Device and method for fronthaul transmission in wireless communication system

ABSTRACT

The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). According to embodiments, a method performed by a distributed unit (DU), the method comprises generating a control plane (C-plane) message for multiple ports, the C-plane message including section information and a section extension; and transmitting the C-plane message to a radio unit (RU) via a specific port of the multiple ports. The section information includes information on a beam identifier (ID). The section extension includes beam group type information for indicating a type of beam grouping, and port information for indicating a total number of one or more extended antenna-carrier (eAxC) ports indicated by the section extension.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application of prior application Ser.No. 17/516,123 filed on Nov. 1, 2021, which has issued as U.S. Pat. No.11,778,632, on Oct. 3, 2023; which is a continuation application ofprior application Ser. No. 17/073,890, filed on Oct. 19, 2020, which hasissued as U.S. Pat. No. 11,166,271 on Nov. 2, 2021; and which was basedon and claimed priority under 35 U.S.C. § 119(a) of a Korean patentapplication number 10-2019-0130251, filed on Oct. 18, 2019, in theKorean Intellectual Property Office, the disclosure of each of which isincorporated by reference herein in its entirety.

BACKGROUND 1) Field

The disclosure relates to a wireless communication system. Moreparticularly, the disclosure relates to a device and method forfronthaul transmission in a wireless communication system.

2) Description of Related Art

To meet the demand for wireless data traffic having increased sincedeployment of 4^(th) generation (4G) communication systems, efforts havebeen made to develop an improved 5^(th) generation (5G) or pre-5Gcommunication system. Therefore, the 5G or pre-5G communication systemis also called a ‘Beyond 4G Network’ or a ‘Post long term evolution(LTE) System’.

The 5G communication system is considered to be implemented in higherfrequency (millimeter (mm) Wave) bands, e.g., 60 gigahertz (GHz) bands,so as to accomplish higher data rates. To decrease propagation loss ofthe radio waves and increase the transmission distance, beamforming,massive multiple-input multiple-output (MIMO), Full Dimensional MIMO(FD-MIMO), array antenna, analog beam forming, and large scale antennatechniques are discussed for use in 5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud RadioAccess Networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul, moving network, cooperativecommunication, Coordinated Multi-Points (CoMP), reception-endinterference cancellation and the like.

In the 5G system, Hybrid frequency shift keying (FSK) and quadratureamplitude modulation (QAM) Modulation (FQAM) and sliding windowsuperposition coding (SWSC) as an advanced coding modulation (ACM), andfilter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA),and sparse code multiple access (SCMA) as an advanced access technologyhave been developed.

As transmission capacity increases in a wireless communication system, afunction split for functionally splitting a base station is applied.According to the function split, a base station may be split into adigital unit (DU) and a radio unit (RU), a fronthaul for communicationbetween the DU and the RU is defined, and transmission via the fronthaulis required.

The above information is presented as background information only toassist with an understanding of the disclosure. No determination hasbeen made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the disclosure.

SUMMARY

Aspects of the disclosure are to address at least the above-mentionedproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the disclosure is to providea device and method for transmitting a control message on a fronthaulinterface.

Another aspect of the disclosure is to provide the device and method forintegrating information common to layers in a single message andtransmitting the information in a wireless communication system.

Another aspect of the disclosure is to provide the device and method forreducing a processing burden and a memory requirement when operating adigital unit (DU) and a radio unit (RU) in the wireless communicationsystem.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

In accordance with an aspect of the disclosure, an operation method of aDU of a base station in a wireless communication system is provided. Themethod includes identifying a designated path among a plurality of pathsof a fronthaul interface that connects the DU and an RU, generating acontrol message for a plurality of layers, and transmitting the controlmessage to the RU via the designated path, wherein the control messageincludes scheduling information for the plurality of layers.

In accordance with another aspect of the disclosure, an operation methodof an RU of a base station in a wireless communication system isprovided. The method includes receiving a control message for aplurality of layers from a DU via a designated path among a plurality ofpaths of a fronthaul interface that connects the RU and the DU,identifying scheduling information for the plurality of layers based onthe control message, and performing communication based on thescheduling information.

In accordance with another aspect of the disclosure, a device of a DU ofa base station in a wireless communication system is provided. Thedevice includes at least one processor, wherein the at least oneprocessor identifies a designated path among a plurality of paths of afronthaul interface that connects the DU and an RU, generates a controlmessage for a plurality of layers, and controls the fronthaul interfaceto transmit the control message to the RU via the designated path,wherein the control message includes scheduling information for theplurality of layers.

In accordance with another aspect of the disclosure, a device of an RUof a base station in a wireless communication system is provided. Thedevice includes at least one transceiver and at least one processor,wherein the at least one processor controls a fronthaul interface, whichconnects the RU and a DU, to receive a control message for a pluralityof layers from the DU via a designated path among a plurality of pathsof the fronthaul interface, identifies scheduling information for theplurality of layers based on the control message, and controls the atleast one transceiver to perform communication based on the schedulinginformation.

According to embodiments, a method performed by a distributed unit (DU),the method comprises generating a control plane (C-plane) message formultiple ports, the C-plane message including section information and asection extension; and transmitting the C-plane message to a radio unit(RU) via a specific port of the multiple ports. The section informationincludes information on a beam identifier (ID). The section extensionincludes beam group type information for indicating a type of beamgrouping, and port information for indicating a total number of one ormore extended antenna-carrier (eAxC) ports indicated by the sectionextension.

According to embodiments, a method performed by a radio unit (RU), themethod comprises: receiving, from a distributed unit (DU), a controlplane (C-plane) message for multiple ports via a specific port of themultiple ports; identifying section information and a section extensionincluded in the C-plane message. The section information includesinformation on a beam identifier (ID). The section extension includesbeam group type information for indicating a type of beam grouping, andport information for indicating a total number of one or more extendedantenna-carrier (eAxC) ports indicated by the section extension.

According to embodiments, a device of a distributed unit (DU), comprisesat least one transceiver; and at least one processor configured togenerate a control plane (C-plane) message for multiple ports, theC-plane message including section information and a section extension;and control the at least one transceiver to transmit the C-plane messageto a radio unit (RU) via a specific port of the multiple ports. Thesection information includes information on a beam identifier (ID). Thesection extension includes beam group type information for indicating atype of beam grouping, and port information for indicating a totalnumber of one or more extended antenna-carrier (eAxC) ports indicated bythe section extension.

According to embodiments, a device of a radio unit (RU), comprises atleast one transceiver; and at least one processor configured to controlthe at least one transceiver to receive, from a distributed unit (DU), acontrol plane (C-plane) message for multiple ports via a specific portof the multiple ports; identify section information and a sectionextension included in the C-plane message including. The sectioninformation includes information on a beam identifier (ID). The sectionextension includes beam group type information for indicating a type ofbeam grouping, and port information for indicating a total number of oneor more extended antenna-carrier (eAxC) ports indicated by the sectionextension.

A device and method according to various embodiments reduces theoperational burden of a DU and an RU by transmitting information on eachlayer via a single control message.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A illustrates a wireless communication system according to anembodiment of the disclosure;

FIG. 1B illustrates an example of a fronthaul structure according to afunction split of the base station according to an embodiment of thedisclosure;

FIG. 2 illustrates a configuration of a digital unit (DU) in thewireless communication system according to an embodiment of thedisclosure;

FIG. 3 illustrates a configuration of a radio unit (RU) in the wirelesscommunication system according to an embodiment of the disclosure;

FIG. 4 illustrates an example of a function split in the wirelesscommunication system according to an embodiment of the disclosure;

FIG. 5 illustrates an example of a control message for multi-layerscheduling according to an embodiment of the disclosure;

FIG. 6 illustrates an example of the DU and the RU for multi-layerscheduling according to an embodiment of the disclosure;

FIG. 7 illustrates an example of a structure of a control messageaccording to an embodiment of the disclosure;

FIG. 8 illustrates an example of control message transmission accordingto an embodiment of the disclosure;

FIG. 9 illustrates another example of control message transmissionaccording to an embodiment of the disclosure;

FIG. 10A illustrates an example of a control plane during multi-layerscheduling according to an embodiment of the disclosure;

FIG. 10B illustrates another example of a control plane duringmulti-layer scheduling according to an embodiment of the disclosure;

FIG. 11 illustrates an operation flow of the DU, for multi-layerscheduling according to an embodiment of the disclosure; and

FIG. 12 illustrates an operation flow of the RU, for multi-layerscheduling according to an embodiment of the disclosure.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components, and structures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thedisclosure. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of thedisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of thedisclosure is provided for illustration purpose only and not for thepurpose of limiting the disclosure as defined by the appended claims andtheir equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

Hereinafter, various embodiments of the disclosure will be describedbased on an approach of hardware. However, various embodiments of thedisclosure include a technology that uses both hardware and software,and thus the various embodiments of the disclosure may not exclude theperspective of software.

In the following description, terms (e.g., message, information,preamble, signal, signaling, sequence, and stream) referring to asignal, terms (e.g., symbol, slot, subframe, radio frame, subcarrier,resource element (RE), resource block (RB), bandwidth part (BWP), andoccasion) referring to a resource, terms (e.g., operation or procedure)referring to an operation state, terms (e.g., user stream, IQ data,information, bit, symbol, and codeword) referring to data, termsreferring to a channel, terms (e.g., downlink control information (DCI),medium access control (MAC) control element (CE), and radio resourcecontrol (RRC) signaling) referring to control information, termsreferring to network entities, terms referring to elements of a device,etc. are illustrated for the convenience of description. Therefore, thedisclosure is not limited to the terms described below, and other termshaving equivalent technical meanings may be used.

In the disclosure, in order to determine whether a specific condition issatisfied or fulfilled, an expression of more/greater/larger than orless/smaller than may be used, but this is only a description forexpressing an example, and does not exclude a description of equal to ormore/greater/larger than or a description of equal to or less/smallerthan. The condition described as “equal to or more/greater/larger than”may be replaced with “more/greater/larger than,” the condition describedas “equal to or less/smaller than” may be replaced with “less/smallerthan,” and the condition described as “equal to or more/greater/largerthan, and less/smaller than” may be replaced with “more/greater/largerthan, and equal to or less/smaller than.”

In the disclosure, various embodiments are described using terms used insome communication standards (e.g., 3rd generation partnership project(3GPP), extensible radio access network (xRAN), and open-radio accessnetwork (O-RAN)), but these are merely examples for description. Variousembodiments of the disclosure may also be easily modified and applied toother communication systems.

FIG. 1A illustrates a wireless communication system according to anembodiment of the disclosure. FIG. 1 illustrates a base station 110, aterminal 120, and a terminal 130, as parts of nodes using a radiochannel in a wireless communication system. FIG. 1 illustrates only onebase station, but may further include another base station that is thesame as or similar to the base station 110.

Referring to FIG. 1A, the base station 110 is a network infrastructurethat provides wireless access to the terminals 120 and 130. The basestation 110 has coverage defined to be a predetermined geographic areabased on the distance over which a signal may be transmitted. The basestation 110 may be referred to as, in addition to “base station,”“access point (AP),” “evolved NodeB (eNodeB) (eNB),” “5G node (5thgeneration node),” “next generation NodeB (gNB),” “wireless point,”“transmission/reception point (TRP),” or other terms having equivalenttechnical meanings.

Each of the terminal 120 and the terminal 130 is a device used by auser, and performs communication with the base station 110 via the radiochannel. A link from the base station 110 to the terminal 120 or theterminal 130 is referred to as a downlink (DL), and a link from theterminal 120 or the terminal 130 to the base station 110 is referred toas an uplink (UL). The terminal 120 and the terminal 130 may communicatewith each other via a radio channel. In this case, a device-to-device(D2D) link between the terminal 120 and the terminal 130 is referred toas a sidelink, and the sidelink may be interchangeably used with a PC5interface. In some cases, at least one of the terminal 120 and theterminal 130 may be operated without involvement of a user. That is, atleast one of the terminal 120 and the terminal 130 is a device thatperforms machine type communication (MTC) and may not be carried by auser. Each of the terminal 120 and the terminal 130 may be referred toas, in addition to “terminal,” “user equipment (UE),” “customer premisesequipment (CPE),” “mobile station,” “subscriber station,” “remoteterminal,” “wireless terminal,” “electronic device,” “user device,” orother terms having equivalent technical meanings.

The base station 110, the terminal 120, and the terminal 130 may performbeamforming. The base station 110, the terminal 120, and the terminal130 may transmit and receive radio signals in a relatively low frequencyband (e.g., frequency range 1 (FR1) of new radio (NR)) as well as a highfrequency band (e.g., FR2 of NR, and a millimeter wave (mmWave) band(e.g., 28 gigahertz (GHz), 30 GHz, 38 GHz, and 60 GHz)). At this time,in order to improve a channel gain, the base station 110, the terminal120, and the terminal 130 may perform beamforming. The beamforming mayinclude transmission beamforming and reception beamforming. That is, thebase station 110, the terminal 120, and the terminal 130 may assign adirectivity to a transmission signal or a reception signal. To this end,the base station 110 and the terminals 120 and 130 may select servingbeams 112, 113, 121, and 131 via a beam search procedure or a beammanagement procedure. After the serving beams 112, 113, 121, and 131 areselected, communication may then be performed via resources that are inquasi co-located (QCL) relationship with resources at which the servingbeams 112, 113, 121, and 131 are transmitted. The base station/terminalaccording to various embodiments may perform communication also within afrequency range corresponding to FR1. The base station/terminal may ormay not perform beamforming.

If large-scale characteristics of a channel, via which a symbol on afirst antenna port has been transferred, can be inferred from a channelvia which a symbol on a second antenna port has been transferred, it maybe estimated that the first antenna port and the second antenna port arein a QCL relationship. For example, the large-scale characteristics mayinclude at least one among a delay spread, a doppler spread, a dopplershift, an average gain, an average delay, and a spatial receiverparameter.

In the disclosure, a beam refers to a spatial flow of a signal in aradio channel, and is formed by one or more antennas (or antennaelements), and this forming procedure may be referred to as beamforming.Beamforming may include analog beamforming and digital beamforming(e.g., precoding). A reference signal transmitted based on beamformingmay be, for example, a demodulation-reference signal (DM-RS), a channelstate information-reference signal (CSI-RS), a synchronizationsignal/physical broadcast channel (SS/PBCH), and a sounding referencesignal (SRS). As a configuration for each reference signal, an IE, suchas a CSI-RS resource or an SRS-resource, may be used, and thisconfiguration may include information associated with a beam. Theinformation associated with a beam may indicate whether theconfiguration (e.g., CSI-RS resource) uses the same spatial domainfilter as that of the other configuration (e.g., another CSI-RS resourcein the same CSI-RS resource set) or uses a different spatial domainfilter, or may indicate a reference signal, with which the configurationis quasi-co-located (QCL), and a type (e.g., QCL type A, B, C, D) of theQCL if the configuration is quasi-co-located.

When storing a beam profile during an RU initialization procedure, thebase station may store a common beam vector and each precoding vector inorder of each layer. Considering of each of all terminals (i.e., users)as one layer and applying a common weight vector (precoder) to eachterminal may be understood as forming a common beam applied to allterminals. Applying a specific precoder for a multi-layer to eachterminal may be understood as single-user beamforming for each terminal.Even if the precoder is applied to the terminals, signals transmitted tosome terminals may be spatially distinguished from signals transmittedto some other terminals. In this case, applying of the correspondingprecoder may be understood as multi-user beamforming.

Conventionally, in a communication system in which a cell radius of abase station is relatively large, each base station is installed so thateach base station includes a function of a digital processing unit (orDU) and a function of a radio frequency (RF) processing unit (RU).However, when a high frequency band is used in a communication system of4th generation (4G) and/or later, and as the cell radius of a basestation decreases, the number of base stations for covering a specificarea has increased, and the burden of installation costs of the operatorfor installation of the increased base stations has increased. In orderto minimize an installation cost of a base station, a structure has beenproposed in which a DU and RUs of the base station are separated so thatone or more RUs are connected to one DU via a wired network, and one ormore RUs distributed geographically are deployed to cover a specificarea. Hereinafter, a deployment structure and extension examples of thebase station according to various embodiments will be described via FIG.1B.

FIG. 1B illustrates an example of a fronthaul structure according to afunction split of the base station according to an embodiment of thedisclosure. Unlike a backhaul between a base station and a core network,a fronthaul is located between entities between a WLAN and a basestation.

Referring to FIG. 1B, the base station 110 may include a DU 160 and anRU 180. A fronthaul 170 between the DU 160 and the RU 180 may beoperated via an F_(x) interface. For the operation of the fronthaul 170,for example, an interface, such as an enhanced common public radiointerface (eCPRI) and radio over Ethernet (ROE), may be used.

With the development of communication technology, mobile data trafficincreases, and accordingly, the amount of bandwidth required in afronthaul between a digital unit and a radio unit has greatly increased.In an arrangement, such as a centralized/cloud radio access network(C-RAN), the DU may be implemented to perform functions for a packetdata convergence protocol (PDCP), a radio link control (RLC), a mediaaccess control (MAC), and a physical (PHY) layer, and the RU may beimplemented to perform more functions for a PHY layer in addition to aradio frequency (RF) function.

The DU 160 may be in charge of an upper layer function of a radionetwork. For example, the DU 160 may perform a function of a MAC layerand a part of a PHY layer. Here, a part of the PHY layer is a functionperformed at a higher stage from among functions of the PHY layer, andmay include, for example, channel encoding (or channel decoding),scrambling (or descrambling), modulation (or demodulation), and layermapping (or layer demapping). According to an embodiment, if the DU 160conforms to the O-RAN standard, it may be referred to as an O-RAN DU(O-DU). The DU 160 may be replaced with and represented by a firstnetwork entity for the base station (e.g., a next generation basestation (gNB)) in embodiments of the disclosure as needed.

The RU 180 may be in charge of a lower layer function of the radionetwork. For example, the RU 180 may perform a part of the PHY layer andthe RF function. Here, a part of the PHY layer is a function performedat a relatively lower stage compared to the DU 160 from among thefunctions of the PHY layer, and may include, for example, an inversefast Fourier transform (FFT) (IFFT) transformation (or FFTtransformation), cyclic prefix (CP) insertion (CP removal), and digitalbeamforming. An example of such a specific function split is describedin detail in FIG. 4 . The RU 180 may be referred to as “access unit(AU),” “access point (AP),” “transmission/reception point (TRP),”“remote radio head (RRH),” “radio unit (RU)” or another term having anequivalent technical meaning. According to an embodiment, if the RU 180conforms to the O-RAN standard, it may be referred to as an O-RAN RU(O-RU). The RU 180 may be replaced with and represented by a secondnetwork entity for the base station (e.g., gNB) in embodiments of thedisclosure as needed.

FIG. 1B shows that the base station includes the DU and the RU, butvarious embodiments are not limited thereto. In some embodiments, thebase station may be implemented to have distributed deployment accordingto a centralized unit (CU) configured to perform a function of an upperlayer (e.g., packet data convergence protocol (PDCP) and RRC) of anaccess network and a distributed unit (DU) configured to perform afunction of a lower layer. The distributed unit (DU) may include thedigital unit (DU) and the radio unit (RU) of FIG. 1 . Between the core(e.g., 5G core (5GC) or next generation core (NGC)) network and theradio network (RAN), the base station may be implemented in a structurewith deployment in the order of the CU, the DU, and the RU. An interfacebetween the CU and the distributed unit (DU) may be referred to as an F1interface.

The centralized unit (CU) may be connected to one or more DUs so as tobe in charge of a function of a layer higher than that of the DUs. Forexample, the CU may be in charge of functions of radio resource control(RRC) and packet data convergence protocol (PDCP) layers, and the DU andthe RU may be in charge of a function of a lower layer. The DU mayperform some functions of the physical (PHY) layer, the media accesscontrol (MAC), and the radio link control (RLC), and the RU may be incharge of the remaining functions (low PHY) of the PHY layer. Forexample, the digital unit (DU) may be included in a distributed unit(DU) according to distributed deployment implementation of the basestation. Hereinafter, unless otherwise defined, descriptions areprovided with operations of a digital unit (DU) and a RU. However,various embodiments may be applied to both base station deploymentincluding a CU or deployment in which a DU is directly connected to acore network without a CU (i.e., a CU and a DU are integrated andimplemented into one entity).

FIG. 2 illustrates a configuration of a DU in the wireless communicationsystem according to an embodiment of the disclosure. The configurationillustrated in FIG. 2 may be understood as the configuration of the DU160 of FIG. 1B, as part of a base station. The terms “-unit,” “-device,”etc. used hereinafter refer to a unit that processes at least onefunction or operation, which may be implemented by hardware or software,or a combination of hardware and software.

Referring to FIG. 2 , the DU 160 includes a communication unit 210, astorage unit 220, and a controller 230.

The communication unit 210 may perform functions for transmitting orreceiving a signal in a wired communication environment. Thecommunication unit 210 may include a wired interface for controlling adirect connection between devices via a transmission medium (e.g.,copper wire and optical fiber). For example, the communication unit 210may transfer an electrical signal to another device through a copperwire, or may perform conversion between an electrical signal and anoptical signal. The communication unit 210 may be connected to the radiounit (RU). The communication unit 210 may be connected to the corenetwork or may be connected to the CU in distributed deployment.

The communication unit 210 may perform functions for transmitting orreceiving a signal in a wired communication environment. For example,the communication unit 210 may perform conversion between a basebandsignal and a bit stream according to the physical layer specification ofa system. For example, when transmitting data, the communication unit210 generates complex symbols by encoding and modulating a transmissionbit stream. When receiving data, the communication unit 210 reconstructsa received bit stream by demodulating and decoding the baseband signal.Also, the communication unit 210 may include a plurality oftransmission/reception paths. According to an embodiment, thecommunication unit 210 may be connected to the core network or may beconnected to other nodes (e.g., integrated access backhaul (IAB)).

The communication unit 210 may transmit or receive a signal. To thisend, the communication unit 210 may include at least one transceiver.For example, the communication unit 210 may transmit a synchronizationsignal, a reference signal, system information, a message, a controlmessage, a stream, control information, data, or the like. Thecommunication unit 210 may perform beamforming.

The communication unit 210 transmits and receives a signal as describedabove. Accordingly, all or a part of the communication unit 210 may bereferred to as “transmitter,” “receiver,” or “transceiver.” In thefollowing description, transmission and reception performed via a radiochannel are used in a sense including processing performed as describedabove by the communication unit 210.

Although not illustrated in FIG. 2 , the communication unit 210 mayfurther include a backhaul communication unit for connecting to the corenetwork or another base station. The backhaul communication unitprovides an interface to perform communication with other nodes withinthe network. That is, the backhaul communication unit converts, into aphysical signal, a bit stream transmitted from the base station toanother node, for example, another access node, another base station, anupper node, the core network, etc., and converts a physical signalreceived from another node into a bit stream.

The storage unit 220 stores data, such as a basic program, anapplication program, and configuration information for operations of theDU 160. The storage unit 220 may include a memory. The storage unit 220may include a volatile memory, a nonvolatile memory, or a combination ofa volatile memory and a nonvolatile memory. The storage unit 220provides stored data in response to a request of the controller 230.According to an embodiment, the storage unit 220 may store schedulinginformation (e.g., beam information and antenna port information) andflow information (e.g., eAxC) for each stream.

The controller 230 may control overall operations of the DU 160. Forexample, the controller 230 transmits and receives a signal via thecommunication unit 210 (or backhaul communication unit). Further, thecontroller 230 records and reads data in the storage unit 220. Thecontroller 230 may perform functions of a protocol stack required by thecommunication standard. To this end, the controller 230 may include atleast one processor. In some embodiments, the controller 230 may includea control message generator including resource allocation informationfor scheduling multiple layers, and a flow identifier for transmissionof a corresponding control message. The control message generator andthe flow identifier are instruction sets or codes stored in the storageunit 230, and may be instructions/codes at least temporarily residing inthe controller 230 or a storage space storing instructions/codes, or maybe a part of a circuitry constituting the controller 230. According tovarious embodiments, the controller 230 may control the DU 160 toperform operations based on the various embodiments described below.

The configuration of the DU 160 illustrated in FIG. 2 is merely anexample, and an example of the DU performing various embodiments of thedisclosure is not limited from the configuration illustrated in FIG. 2 .That is, according to various embodiments, some elements may be added,deleted, or changed.

FIG. 3 illustrates a configuration of an RU in the wirelesscommunication system according to an embodiment of the disclosure. Theconfiguration illustrated in FIG. 3 may be understood as theconfiguration of the RU 180 of FIG. 1B, as part of the base station. Theterms “-unit,” “-device,” etc. used hereinafter refer to a unit thatprocesses at least one function or operation, which may be implementedby hardware or software, or a combination of hardware and software.

Referring to FIG. 3 , the RU 180 includes a communication unit 310, astorage unit 320, and a controller 330.

The communication unit 310 performs functions for transmitting orreceiving a signal via a radio channel. For example, the communicationunit 310 up-converts a baseband signal into an RF band signal, transmitsthe up-converted RF band signal via an antenna, and then down-convertsthe RF band signal received via the antenna into a baseband signal. Forexample, the communication unit 310 may include a transmission filter, areception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC,and the like.

Also, the communication unit 310 may include a plurality oftransmission/reception paths. Further, the communication unit 310 mayinclude an antenna unit. The communication unit 310 may include at leastone antenna array including multiple antenna elements. In terms ofhardware, the communication unit 310 may include a digital circuit andan analog circuit (e.g., radio frequency integrated circuit (RFIC)). Thedigital circuit and the analog circuit may be implemented in a singlepackage. The communication unit 310 may include a plurality of RFchains. The communication unit 310 may perform beamforming. In order togive directivity according to a configuration of the controller 330 to asignal to be transmitted or received, the communication unit 310 mayapply a beamforming weight to the signal. According to an embodiment,the communication unit 310 may include a radio frequency (RF) block (orRF unit).

The communication unit 310 may transmit or receive a signal. To thisend, the communication unit 310 may include at least one transceiver.The communication unit 310 may transmit a downlink signal. The downlinksignal may include a synchronization signal (SS), a reference signal(RS) (e.g., cell-specific reference signal (CRS) and a demodulation(DM)-RS), system information (e.g., MIB, SIB, remaining systeminformation (RMSI), and other system information (OSI)), a configurationmessage, control information, downlink data, or the like. Thecommunication unit 310 may receive an uplink signal. The uplink signalmay include a random access-related signal (e.g., a random accesspreamble (RAP) (or message 1 (Msg1) and message 3 (Msg3)) or a referencesignal (e.g., a sounding reference signal (SRS), and a DM-RS), a powerheadroom report (PHR), or the like.

The communication unit 310 transmits and receives a signal as describedabove. Accordingly, all or a part of the communication unit 310 may bereferred to as “transmitter,” “receiver,” or “transceiver.” In thefollowing description, transmission and reception performed via awireless channel are used in a sense including processing performed asdescribed above by the wireless communication unit 310.

The storage unit 320 stores data, such as a basic program, anapplication program, and configuration information for operations of theRU 180. The storage unit 320 may include a volatile memory, anonvolatile memory, or a combination of a volatile memory and anonvolatile memory. The storage unit 320 provides stored data inresponse to a request of the controller 330.

The controller 330 controls overall operations of the RU 180. Forexample, the controller 330 transmits and receives a signal via thecommunication unit 310. The controller 330 records and reads data in thestorage unit 320. The controller 330 may perform functions of a protocolstack required by the communication standard. To this end, thecontroller 330 may include at least one processor. The controller 330may include various modules for performing communication. According tovarious embodiments, the controller 330 may control a terminal toperform operations based on various embodiments described below.

FIG. 4 illustrates an example of a function split in the wirelesscommunication system according to an embodiment of the disclosure. Withthe advancement of wireless communication technology (e.g., 5thgeneration communication system (or the introduction of new radio (NR)communication system)), a use frequency band has increased more andmore, and as a cell radius of a base station becomes very small, thenumber of RUs required to be installed has further increased. In a 5Gcommunication system, the amount of transmitted data has increased by 10times or more, and the transmission capacity of a wired network, whichis transmitted via a fronthaul, has increased significantly. Due tothese factors, the installation cost of a wired network in a 5Gcommunication system may increase significantly. Therefore, in order tolower the transmission capacity of the wired network and reduce theinstallation cost of the wired network, techniques for lowering thetransmission capacity of the fronthaul by transferring some functions ofa modem of a DU to a RU have been proposed, and these techniques may bereferred to as “function split.”

In order to reduce the burden on the DU, a method of extending a role ofthe RU, which is in charge of only an RF function, to some functions ofa physical layer is considered. In this case, as the RU performsfunctions of a higher layer, the throughput of the RU increases, so thata transmission bandwidth in the fronthaul may increase, while delay timerequirement constraint due to response processing decreases. As the RUperforms the functions of a higher layer, the virtualization gaindecreases and the size/weight/cost of the RU increases. In considerationof the trade-off of the advantages and disadvantages described above, itis required to implement an optimal function split.

Referring to FIG. 4 , function splits in a physical layer below a MAClayer are shown. In the case of a downlink (DL) that transmits a signalto a terminal via the radio network, the base station may sequentiallyperform channel encoding/scrambling, modulation, layer mapping, antennamapping, RE mapping, digital beamforming (e.g., precoding), IFFTtransform/CP insertion, and RF conversion. In the case of an uplink (UL)that receives a signal from a terminal via the radio network, the basestation may sequentially perform RF conversion, FFT transform/CPremoval, digital beamforming (pre-combining), RE demapping, channelestimation, layer demapping, demodulation, and decoding/descrambling.Separation of uplink functions and downlink functions may be defined invarious types by the necessity between vendors, discussion onspecifications, etc. according to the trade-off described above.

A first function split 405 may be separation of an RF function and a PHYfunction. The first function split is that the PHY function in the RU isnot substantially implemented, and may be referred to as, for example,option 8. A second function split 410 enables the RU to perform the PHYfunction that is to perform IFFT transform/CP insertion in the DL andFFT transform/CP removal in the UL, and enables the DU to perform theremaining PHY functions. For example, the second function split 410 maybe referred to as option 7-1. A third function split 420 a enables theRU to perform the PHY function that is to perform IFFT transform/CPinsertion in the DL and FFT transform/CP removal and digital beamformingin the UL, and enables the DU to perform the remaining PHY functions.For example, the third function split 420 a may be referred to as option7-2x category A. A fourth function split 420 b enables the RU to performup to digital beamforming in both the DL and UL, and enables the DU toperform higher PHY functions after the digital beamforming. For example,the fourth function split 420 b may be referred to as option 7-2xcategory B. A fifth function split 425 enables the RU to perform up toRE mapping (or RE demapping) in both the DL and UL, and enables the DUto perform higher PHY functions after the RE mapping (or RE demapping).For example, the fifth function split 425 may be referred to as option7-2. A sixth function split 430 enables the RU to perform up tomodulation (or demodulation) in both the DL and UL, and enables the DUto perform higher PHY functions after the modulation (or demodulation).For example, the sixth function split 430 may be referred to as option7-3. A seventh function split 440 enables the RU to perform up toencoding/scrambling (or decoding/descrambling) in both the DL and UL,and enables the DU to perform higher PHY functions after the modulation(or demodulation). For example, the seventh function split 440 may bereferred to as option 6.

According to an embodiment, when large-capacity signal processing isexpected, such as the FR1 MMU, a function split (e.g., the fourthfunction split 420 b) at a relatively high layer may be required toreduce a fronthaul capacity. In a function split (e.g., the sixthfunction split 430) at a layer that is too high, a control interfacebecomes complex, and the burden on the implementation of the RU may becaused due to a plurality of PHY processing blocks included in the RU,so that an appropriate function split may be required according to adeployment and implementation scheme for the DU and the RU.

According to an embodiment, if precoding of data received from the DU isunable to be processed (i.e., if there is a limit to the precodingcapability of the RU), the third function split 420 a or a lowerfunction split (e.g., the second function split 410) may be applied.Conversely, if there is an ability to process the precoding of datareceived from the DU, the fourth function split 420 b or a higherfunction split (e.g., the sixth function split 430) may be applied.Hereinafter, various embodiments are described based on the thirdfunction split 420 a or the fourth function split 420 b unless otherwiselimited, but configurations of the embodiments via other function splitsare not excluded. That is, in a situation of the sixth function split430 (option 7-3), operations of the DU and RU for control messagetransmission in FIG. 5 to FIG. 12 described below may be applied.

Fronthaul Control Message for Multi-Layer Scheduling

In order to increase intra-cell transmission capacity, a base stationmay perform multi-layer transmission to a terminal. The base station maygenerate a plurality of streams and may transmit the streams to theterminal within one TTI. Each stream may be transmitted via an antennacorresponding to the corresponding stream. Each transmission stream isspatially divided via the antenna. In this case, as the number of layersincreases, the throughput required by the base station in a fronthaulbetween a DU and an RU increases. This problem may occur in a case of anuplink in which the terminal transmits data to the base station, as wellas in a case in which the base station transmits data to the terminal.Accordingly, in FIG. 5 to FIG. 12 , a scheme for transmitting controlinformation (e.g., resource allocation information, beam allocationinformation, scheduling information, etc.) more efficiently duringmulti-layer scheduling in a fronthaul structure according to a functionsplit between the DU and the RU is described.

For describing Section type, the following section types are supportedwithin the C-Plane.

Section Type Target Scenario Remarks 0 Unused Resource Indicates to O-RUthat certain Resource Blocks Blocks or symbols in or symbols will not beused (idle periods, guard Downlink or Uplink periods). Likewise, thereare no associated U- Plane messages containing IQ data for this SectionType. 1 Most DL/UL radio Here “most” refers to channels not requiringchannels time or frequency offsets such as are needed formixed-numerology channels 2 reserved for future use 3 PRACH and mixed-Channels requiring time or frequency offsets or numerology channelsdifferent-than-nominal SCS values 4 Reserved for further use 5 UEscheduling Provides scheduling information for UE-IDs information (UE-IDassignment to section) 6 Channel information Sends UE-specific channelinformation from the O-DU to the O-RU 7 LAA Messages communicatedbetween O-DU and the O-RU in both directions to configure LBT forPDSCH/DRS transmission and to report the LBT outcome.

FIG. 5 illustrates an example of a control message for multi-layerscheduling according to an embodiment of the disclosure. In a case of aDL, a DU may transfer, to an RU, whether a resource is scheduled (e.g.,a pattern on RE mapping), beam information to be applied to a scheduledresource, and user data. In a case of a UL, the DU may transmit, like inthe case of DL, whether scheduling is performed and beam information forthe scheduling resource to the RU, and the RU may transfer user data tothe DU. In order to reduce the burden of a fronthaul between the DU andthe RU, a small capacity, fewer resources, and a flexible interfacebetween the DU and the RU are required.

Referring to FIG. 5 , a situation in which a base station transmits datastreams having N (N is an integer greater than 1) layers to a terminalis described. A DU 560 may transmit N data streams to an RU 580. The DU560 may also transmit control information corresponding to each datastream to the RU 580.

User data between the DU 560 and the RU 580 is classified in units oflayers, and therefore a transmission path/or a reception path may bedistinguished between layers. Classification by layer may provide easeof transmission and queue management, by processing transmission andreception of user data streams in parallel. As the number of layersincreases, the amount of control information for management of thelayers also inevitably increases. Assume a situation in which a controlmessage is configured for each of N pieces of user data. The DU 560 maytransmit a total of N control messages (a first control message 510-1, asecond control message 510-2, . . . , an N-th control message 510-N) tothe RU 580. The RU 580 is required to process individual controlmessages to process user data corresponding to each layer. This increasein the number of layers may cause an increase in memory and processingcosts for control message processing in the RU. Information commonlyapplied to each user data, in information included in the controlmessages, is received and processed in duplicate by the RU, andtherefore an overhead may occur.

If a common beam is applied to all layers, a method of transmitting acontrol message via an integrated extended antenna-carrier (eAxC) may beconsidered. However, in this case, as in a case where the RU 580 doesnot have a precoding capability (e.g., the third function split 420 a ofFIG. 4 ), there is a difficulty in that operations are limitedlyperformed. When designing a control message in consideration of thecapability of the RU 580 and a type of the function split, it ispossible to influence a DU configuration, and therefore a design of thecontrol message, which is to integrate and transmit scheduling patternsfor multiple layers into one control message, is required.

In order to address the above-described problem, various embodimentsdescribe a method for a DU to transfer, to an RU, a simplified controlmessage for multiple layers when scheduling for multiple layers isperformed. The DU 560 may transmit, to the RU 580, one control message520 for multiple pieces of user data N according to multi-layertransmission. This control message may be in the form in which N controlmessages (the first control message 510-1, the second control message510-2, . . . , the N-th control message 510-N) that are individuallytransmitted are integrated. The DU 560 may generate the control messageincluding control information commonly applied to layers (user data) andcontrol information applied to each layer. According to an embodiment,if there is no control parameter applied differently to each layer,control information applied to each layer may be omitted in the controlmessage. According to an embodiment, if the control information appliedin common to some layers (two or more layers) among all layers, thecontrol message may include the control information for those layers.The control message may be referred to as a compact control message, asimplified control message, a representative control message, anintegrated control message, a multi-layer-based control message, or thelike.

By designing the control message so as to reduce repetitive overhead andreduce processing load and memory requirements, a fronthaul transmissioncapacity may be reduced. Not only when a common beam is applied to alllayers, but also when a beam is allocated for each user (single userMIMO (SU-MIMO) case) and when spatially separated precoding is appliedto each user (e.g., multi user MIMO (MU-MIMO) case), fewer resources maybe required for information processing in the fronthaul, by defining arelatively compact control message.

Design for Fronthaul Control Message

FIG. 6 illustrates an example of the DU and the RU for multi-layerscheduling according to an embodiment of the disclosure.

Referring to FIG. 6 , eCPRI and O-RAN standards are exemplarilydescribed as fronthaul interfaces when a message is transmitted betweena DU and an RU. An eCPRI header, an O-RAN header, and an additionalfield may be included in an Ethernet payload of a message. Hereinafter,various embodiments will be described using standard terms of the eCPRIor O-RAN, but other expressions having the equivalent meaning as eachterm may be substituted and used in the various embodiments.

For a fronthaul transport protocol, Ethernet and eCPRI, which enableeasy sharing with a network, may be used. The eCPRI header and the O-RANheader may be included in the Ethernet payload. The eCPRI header may belocated at the front end of the Ethernet payload. The contents of theeCPRI header are as follows.

ecpriVersion (4 bits): 0001b (fixed value)

ecpriReserved (3 bits): 0000b (fixed value)

ecpriConcatenation (1 bit): 0b (fixed value)

ecpriMessage (1 byte): Message type

ecpriPayload (2 bytes): Payload size in bytes

ecpriRtcid/ecpriPcid (2 bytes): x, y, and z may be configured via amanagement plane (M-plane). A corresponding field may indicate atransmission path (extended antenna-carrier (eAxC) in the eCPRI) of acontrol message according to various embodiments during multi-layertransmission.

CU_Port_ID (x bits): A channel card is classified. Classification ispossible including up to a modem (2 bits for channel card, and 2 bitsfor Modem).

BandSector_ID (y bits): Classification is performed according tocell/sector.

CC_ID (z bits): Classification is performed according to a componentcarrier.

RU_Port_ID (w bits): Classification is performed according to layer, T,antenna, etc.

ecpriSeqid (2 bytes): A sequence ID is managed for eachecpriRtcid/ecpriPcid, and a sequence ID and a subsequence ID areseparately managed. Radio-transport-level fragmentation is possible if asubsequence ID is used (different from application-level fragmentation).

An application protocol of the fronthaul may include a control plane(C-plane), a user plane (U-plane), a synchronization plane (S-plane),and a management plane (M-plane).

The control plane may be configured to transmit section information andbeam information via a control message. The section information islayer-specific information, and may include information relating toresources allocated in one slot (e.g., 14 symbols). In the controlplane/user plane, a section may refer to an area in which resources areallocated. For example, one section may represent, in a resource gridrepresented by time-frequency resources, resource allocation areas foran area ranging from one RB to 273 RBs for a frequency domain and anarea up to 14 symbols for a time domain. That is, the sectioninformation may include resource allocation information forcommunication between the RU and a terminal.

The beam information is beam information for each section/or layer, andmay indicate a beam applied to a corresponding layer. The beaminformation is a method for indicating a beam, and may includeparameters directly indicating a weight vector (or a weight matrixaccording to an embodiment) applied to form a beam, and may includepredefined weight vectors or an indicator (e.g., a beam ID and aprecoding indicator) indicating a resource to which a specific beam hasbeen applied. In addition to information indicating which beam (whichprecoding) is applied, the beam information may include at least one ofinformation indicating a type of a beam applied to layers, a user IDcorresponding to a layer, or an antenna port number. The beaminformation is information on digital beamforming and indicatesprecoding. Precoding may determine how a data stream corresponding toeach layer is divided and transmitted via transmission antennas. Thebeam information in each layer refers to an index indicating a weightvector having a size of [1×Nt], an indicator (e.g., PMI, CRI, or i₁)indicating a weight matrix, or a weight vector value itself. Here, Nt isthe number of antennas. Beam information in an i-th layer may correspondto an i-th column of the precoding matrix.

The user plane may include downlink data or uplink data of a user. Theweight vector of the above-described beam information may be multipliedby user data (IQ data).

The management plane may be related to an initial setup, a non-realtimereset or reset, and a non-realtime report.

Referring to FIG. 6 , a situation in which a DU 660 transmits a controlmessage to an RU 680 is described. The control message may includesection information and beam information for a corresponding datastream. Assume a multi-layer transmission situation. In order totransmit a total of N data streams, control information for each datastream is required to be provided to the RU 680. A processor (e.g., aCPU of the control plane) of the DU 660 may transmit a control messagecorresponding to each layer via an eAxC corresponding to each layer. Inthis case, the DU 660 may transmit a total of N control messages (afirst control message 610-1, a second control message 610-2, a thirdcontrol message 610-3, . . . , an N-th control message 610-N) to the RU680. A total of N pieces of section information and a total of N piecesof beam information may be provided to the RU 680. However, informationgenerally transmitted in multi-layer transmission is the same or similarexcept for beam information. Accordingly, if the RU 680 is capable ofsharing information with a plurality of eAxCs, transmission of identicalinformation may be duplicated to the RU 680, thereby acting as anoverhead.

The DU 660 according to various embodiments may transmit one controlmessage 620 for a total of N layers to the RU 680. The DU 660 mayidentify a transmission path for control message transmission. The RU680 may receive the control message via the identified reception path.The transmission path (or reception path) of each layer may correspondto an extended antenna-carrier (eAxC) in the eCPRI. The eAxC may referto an antenna-specific data flow for each carrier in a sector. That is,the eAxC may be a unit of a signal flow that may be spatiallydistinguished. The DU 660 may identify an eAxC for transmission of thecontrol message. A representative eAxC for N (N is an integer greaterthan or equal to 1) eAxCs may be previously designated.

According to various embodiments, a representative eAxC ispre-designated for the DU and the RU via a service non-realtime OAMdomain (ORAN M-plane) interface, and the DU 660 may identify thedesignated eAxC when multi-layer transmission is performed or when thecontrol message is transmitted. For the management plane (M-plane), aplurality of eAxCs and one representative eAxC ID may be designated,such as “eAxC ID #A={eAxC ID #0, eAxC ID #1, eAxC ID #2, eAxC ID#(N−1)}, where A is #0-#(N−1).” In some embodiments, a representativeeAxC for each group among a plurality of eAC groups may bepre-designated (e.g., each of a representative eAxC for a first groupand a representative eAxC for a second group exists). In some otherembodiments, one or more eAxCs for all eAxCs may be pre-designated(e.g., a set including one or more eAxCs having representativenessexists). One or more eAxCs may be prioritized. For transmission of theintegrated control message, a required number of eAxCs may be used forthe control message transmission in priority order.

The DU 660 according to various embodiments may generate a controlmessage to be transmitted via an identified path (representative eAxC).The control message may be an integrated message including informationon a total of N layers. By configuring the control message so that thecontrol message does not include section information/beam informationfor one layer, but includes section information for multiple layers andbeam information for each of the layers, an overhead in the fronthaulmay be reduced. For a configuration of this control message, a new fieldmay be added to the control message. The DU may transmit the controlmessage on a control plane section by attaching a new extension field, a“section extension” field. According to an embodiment, the “sectionextension” field may be added to the control message based on ExtType=8of the ORAN WG4 CUS standard. ExtType defines a type for sectionextension on the control plane (C-plane). A new type of an extensionformat may be defined based on ExtType=8. For example, this “sectionextension” field may be applied when the section type of the controlmessage is 1, 3, or 5. A beam ID field in the control message, to whichthe “section extension” field is attached, may refer to a weight matrixinstead of a beam weight vector based on beam group type information(beamGroupType) in the “section extension” field. According to anotherembodiment, the “section extension” field may be added to the controlmessage based on ExtType=7 of the ORAN WG4 CUS standard. A new controlmessage may be configured by modifying a part of the field according tothe existing ExtType.

The extension field in the control message may further include controlinformation for layers. For example, the extension field may be definedas shown in the following table.

TABLE 1 0 1 2 3 4 5 6 7 ef extType = 0 × 08 1 Octet N extLen = 0 × 01 1Octet N + 1 beamGroupType reserved 1 Octet N + 2 reserved 1 Octet N + 3

The “ef” may indicate whether a section extension exists. For example,if “ef” is 1, this may indicate the existence of the section extensionfield, and if “ef” is 0, this may indicate the absence of the sectionextension field. “ExtType” refers to a type of the extension field, and“extLen” refers to a length of the extension field in the number ofbytes. According to an embodiment, a “beamGroupType” field may be addedas a payload in the extension field. For example, the “beamGroupType”field is 2 bits and may be configured to indicate a scheduling scheme ofbeamID in the control message.

In some embodiments, the extension field in the control message mayfurther include control information for an individual layer. Forexample, the extension field may be defined as shown in the followingtable.

TABLE 2 0 1 2 3 4 5 6 7 ef extType = 0 × 08 1 Octet N extLen = 0 × 03 1Octet N + 1 beamGroupType numPortc = 0 × 03 1 Octet N + 2 bif = 1b 2stport beamID[14:8] (or ueID[14:8]) var Octet N + 3 2st port beamID[7:0](or ueID[7:0]) var Octet N + 4 bif = 1b 3nd port beamID[14:8] (orueID[14:8]) var Octet N + 5 3nd port beamID[7:0] (or ueID[7:0]) varOctet N + 6 bif = 1b 4rd port beamID[14:8] (or ueID[14:8]) var Octet N +7 4rd port beamID[7:0] (or ueID[7:0]) var Octet N + 8 bif = 0b reservedvar Octet N + 9 reserved var Octet N + 10 reserved var Octet N + 11

The “bif (beam identification field)” is an indicator indicating theexistence of a beam ID of a subsequent Octet, and an x-th port beamIDrepresents beam information for an individual layer. The beamID of a 1stport may be included in an O-RAN header in the control message. In somecases, the ‘bif’ field may be omitted. A “beamGroupType” field is 2 bitsand may be configured to indicate a scheduling scheme for layers in thecontrol message. For example, the “beamGroupType” field may beconfigured as shown in the following table.

TABLE 3 Scheduling beamGroupType Case Description 00b Common beamID inthe section is used as a common beam beam ID for the “numPortc” ports infront among the ports grouped by M-plane. In this case, extLen = 0x01.This type is not used for Section type 5 01b Single The consecutive“numPortc” beamIDs User subsequent to the beamID in the section apply tothe “numPortc” ports. In this case, extLen = 0x01. This type is not usedfor Section type 5. The beamIDs comprising a beam matrix should bestored at RU. ‘01b’ indicates beam matrix indication. 10b Multi- beamIDslisted in the section extension User apply to the “numPortc” ports.BeamID. “numPortc” beam ID or ueID should be included. ‘10b’ indicatesbeam vector listing. 11b N/A reserved

The “numPortc” may indicate the number of ports (or the number of layersor the number of transmission/reception (Tx/Rx) paths) indicated by theextension field. According to the standard, 64 ports may be indicated.The “bif” may be an indicator indicating the existence of a beam ID of asubsequent Octet. In some cases, the ‘bif’ field may be omitted. Asingle user and multiple users are distinguished according to whetheroverlap occurs during scheduling in a designated frequency domain (e.g.,one or more RBs). For example, resource allocation within the same RBrange may correspond to a multi-user schedule.

The extension fields and individual structures in Tables 1 to 3 can bemodified in a manner that is obvious to those skilled in the art.

FIG. 7 illustrates an example of a structure of a control messageaccording to an embodiment of the disclosure. A multi-layer transmissionsituation for four streams is described as an example.

Referring to FIG. 7 , a control message set 700 includes layer-specificcontrol messages 711, 712, 713, and 714 without an extension fieldaccording to various embodiments. Octet 1 to octet 7 of a controlmessage may correspond to an eCPRI header. Except forecpriRtcid/ecpriPcid indicating a transmission path (eAxC) within theeCPRI header, other parameters may be common to layers. Octet 9 to octet24 of the control message may correspond to the eCPRI header. In someembodiments, parameters of an O-RAN header may be common to layers. Insome embodiments, some of parameters of the O-RAN header may be commonto layers, and some parameters, such as beamID, may be configureddifferently for each layer. When the layer-specific control messages711, 712, 713, and 714 are transmitted, information commonly applied toeach layer is received and processed in duplicate by an RU, so anoverhead may occur.

In order to address the above-described problem, a DU may transmit acontrol message 750 to the RU. The control message 750 may be in theform in which the control messages 711, 712, 713, and 714 areintegrated. According to an embodiment, the control messages 711, 712,713, and 714 may have common parameters in another header, except forecpriRtcid/ecpriPcid. Accordingly, the control message 750 may beconfigured via the existing eCPRI header and O-RAN header. Octets 1 to 4and 6 to 24 of the control message 750 may be the same as those of theindividual control messages 711, 712, 713 and 714, except for theecpriRtcid/ecpriPcid of Octet 5. Octet 5 may be configured to indicatean ID of an eAxC designated as a representative (e.g., eAxC ID=0). Whenmulti-layer transmission is performed, the DU may configure the controlmessage 750 based on the representative eAxC and header parameters atthe time of transmitting an individual layer.

The control message 750 may include an extension field 760 according tovarious embodiments. According to an embodiment, when all controlparameters are commonly applied to layers, an extension field 760 may beconfigured as shown in Table 1. The extension field 760 of Table 1 maybe added to Octets 25 to 28. The “beamGroupType” may indicate 00b. Aweight vector indicated by “beamID” of octets 23 and 24 may be commonlyapplied to layers. Further, “numPortc” is the number of ports formulti-layer transmission and may indicate 4.

FIG. 7 illustrates an embodiment in which an extension field is added tothe control message according to Table 1, but embodiments of thedisclosure are not limited thereto. Other types of extension fields maybe defined. According to an embodiment, an extension field may beconfigured as shown in Table 2.

According to an embodiment, the extension field 760 may include a beamgroup indicator. The weight vector (or weight matrix) applied duringsignal transmission may be configured by two stages. A beam group may beindicated in stage 1, and a beam within the beam group may be indicatedin stage 2. The extension field 760 may include a beam group indicator.A beam ID in a header may be configured to indicate a beam in the beamgroup. If the beam group indicator does not need to be changed, the beamgroup indicator may be intermittently omitted in the extension field760. By indicating a group and indicating an individual beam in thegroup, the number of bits occupied by beam IDs for layers may bedecreased. This is because the beam group of each of layers is the same,but the individual beams may be different. Beam ID information in anexisting section may be recycled by reducing the amount of beam ID viastage 2 indication. According to an additional embodiment, in a case ofMU-MIMO, the extension field 760 may further include an individual beamID for each of the layers from a second layer (after the first layer).The beam ID in the extension field 760 may also be configured toindicate a beam in the beam group.

According to an embodiment, the extension field 760 may include a groupidentifier. The group identifier may indicate a group to which a layerbelongs. The group may represent a group to which an identical weightmatrix is applied. For example, the group identifier may be configuredin the form of a bitmap according to the sizes of layers. “0” mayindicate a first group, and “1” may indicate a second group. The bitmapmay indicate scheduling via MU-MIMO. If all bitmaps are 0, the groupidentifier may indicate scheduling via a common beam. If all bitmaps are1, the group identifier may indicate scheduling via SU-MIMO. For anotherexample, the group identifier may be configured by a layer classifier.For example, if a control message for a total of four layers isconfigured, a value of “0” may indicate scheduling via a common beam, avalue of “1” may indicate MU-MIMO scheduling according to two layers foreach terminal, and a value of “4” may indicate single user scheduling.

FIG. 8 illustrates an example of control message transmission accordingto an embodiment of the disclosure. A situation, in which resourceallocation for four layers of a single user is performed, isillustrated. A DU may generate a control message indicating resourceallocation and beam information for each terminal according to ascheduling result. The horizontal axis represents a frequency domain andthe vertical axis represents a layer.

Referring to FIG. 8 , resources for UE #0 are allocated in a firstfrequency domain over layer #0 to layer #3, resources for UE #1 areallocated in a second frequency domain over layer #0 to layer #3, andresources for UE #2 are allocated in a third frequency domain over layer#0 to layer #3 (800). Referring to a control plane 810, a total of 4individual control messages are transmitted. Since the number of ranksof UE #0 is 4, the number of ranks of UE #1 is 4, and the number ofranks of UE #2 is 2, the maximum number of ranks of UE #0, UE #1 and UE#2 is 4. A control message should be transmitted for each layer, and themaximum rank between terminals, on which scheduling is performed, is 4,so that a total of 4 control messages may be required. Although anidentical beam (beam #0) is provided to layers and terminals, it isinefficient to transmit four control messages on the control plane, andtherefore one integrated control message may be proposed.

Referring to a control plane 820, one integrated control message istransmitted. In order to configure the control message, the parametersin Table 1 may be configured as follows.

Section Configuration: An eCPRI header and an O-RAN header may be used.

-   -   eAxC ID=#0 (representative): A designated path among multiple        layers is indicated. A representative designated path is        indicated. #0 is merely exemplary, and according to an        embodiment, it is also possible to map an arbitrary eAxC ID        (e.g., #0, #1, . . . , #N−1) as a representative.    -   Beam ID=#0 (common beam): A beam commonly applied to all        terminals is indicated.

Section Extension Configuration

-   -   beamGroupType=00b: A beam scheduling scheme according to Table 3        is indicated.    -   numPortc=4: A total number of layers is 4. According to an        embodiment, if the beam scheduling scheme is 00b, the number of        layers may be omitted.

FIG. 9 illustrates another example of control message transmissionaccording to an embodiment of the disclosure. A situation, in whichresource allocation for up to a total of eight layers is performed in asituation where single-user scheduling and multi-user scheduling aremixed, is illustrated. A DU may generate a control message indicatingresource allocation and beam information for each terminal according toa scheduling result. The horizontal axis represents a frequency domainand the vertical axis represents a layer.

Referring to FIG. 9 , resources for UE #0 are allocated in a firstfrequency domain over layer #0 to layer #3, resources for UE #0, UE #1,UE #2, and UE #3 are allocated in a second frequency domain over layer#0 to layer #7, and resources for UE #1 are allocated in a thirdfrequency domain over layer #0 and layer #1 (900). Referring to acontrol plane 910, a total of 14 individual control messages aretransmitted. The number of ranks of UE #0 is 4, the number of ranks ofUE #1 is 2, the number of ranks in a second resource area is 8, andtherefore layers requiring full scheduling may be classified to be 14. Acontrol message should be transmitted for each layer, and thus a totalof 14 control messages may be required. Although scheduling for SU-MIMOis performed in a first and a third resource area and scheduling forMU-MIMO is performed in a second resource area, fronthaul resources maybe wasted due to configuration of the control message for each layer.Therefore, one integrated control message may be proposed for eachscheduling scheme.

Referring to a control plane 920, a total of three integrated controlmessages are transmitted. One integrated control message is transmittedfor each frequency domain. In order to configure the control message,the parameters in Table 1 or Table 2 may be configured as follows.

Section Configuration: An eCPRI header and an O-RAN header may be used.

-   -   eAxC ID=#0 (representative): A designated path among multiple        layers is indicated. A representative designated path is        indicated. #0 is merely exemplary, and according to an        embodiment, it is also possible to map an arbitrary eAxC ID        (e.g., #0, #1, . . . , #N−1) as a representative.    -   Beam ID=#0: A beam for layers of a single terminal or a beam        applied to a first layer is indicated.

First Section Extension Configuration—a First Resource Area

-   -   beamGroupType=01b: A beam scheduling scheme according to Table 3        is indicated.    -   numPortc=4: A total number of layers is 4.

Second Section Extension Configuration—a Second Resource Area

-   -   beamGroupType=10b: A beam scheduling scheme according to Table 3        is indicated.    -   numPortc=8: A total number of layers is 8.    -   beamID #1-#7 (or UE IE #1-#7): A beamID for each layer is        defined. A beam ID for the first layer may be included in a        section configuration. It has been described that a beamID is        configured for each layer. However, according to an embodiment,        a reduced number of beam IDs may be included according to the        size of a beam matrix.

Third Section Extension Configuration—a Third Resource Area

-   -   beamGroupType=01b: A beam scheduling scheme according to Table 3        is indicated.    -   numPortc=2: A total number of layers is 2.

FIG. 10A illustrates an example of a control plane during multi-layerscheduling according to an embodiment of the disclosure. A situation, inwhich resource allocation is performed in a situation where single-userscheduling and multi-user scheduling are mixed, is illustrated. A DU maygenerate a control message indicating resource allocation and beaminformation for each terminal according to a scheduling result. Thehorizontal axis represents a frequency domain and the vertical axisrepresents a layer.

Referring to FIG. 10A, resources for UE #0 are allocated in a firstfrequency domain 1010 over layer #0 to layer #3, resources for UE #0, UE#1, UE #2, and UE #3 are allocated in a second frequency domain 1020over layer #0 to layer #7, and resources for UE #1 are allocated in athird frequency domain 1030 over layer #0 and layer #1 (1000). Whenscheduling for multiple users is performed in the second frequencydomain 1020, any beam may be allocated to an area without user data,that is, an area in which all user IQ data is 0. Accordingly, not all UE#1, UE #2, and UE #3 use the second frequency domain 1020 in layer #4 tolayer #7, but for ease of configuration of the control message, a beamallocated to a scheduled resource of the second frequency domain 1020may be also equally allocated to an unscheduled resource (1005).

FIG. 10B illustrates another example of a control plane duringmulti-layer scheduling according to an embodiment of the disclosure. Asituation, in which resource allocation is performed in a situationwhere single-user scheduling and multi-user scheduling are mixed, isillustrated. A DU may generate a control message indicating resourceallocation and beam information for each terminal according to ascheduling result. The horizontal axis represents a frequency domain andthe vertical axis represents a layer.

Referring to FIG. 10B, resources for UE #0 are allocated in a firstfrequency domain 1060 over layer #0 to layer #3, resources for UE #0, UE#1, UE #2, UE #3, and UE #4 are allocated in a second frequency domain1070 over layer #0 to layer #7, and resources for UE #1 are allocated ina third frequency domain 1080 over layer #0 and layer #1 (1050).

When scheduling for multiple users is performed in the second frequencydomain 1070, any beam may be allocated to an area without user data,that is, an area in which all user IQ data is 0. Not all UE #1, UE #2,UE #3, and UE #4 use the second frequency domain 1070 in layer #4 tolayer #7, but for ease of configuration of the control message, a beamallocated to a scheduled resource of the second frequency domain 1070may be also equally allocated to an unscheduled resource. However,unlike FIG. 10A, in layer #7 of FIG. 10B, not only UE #3 but also UE #4are scheduled in the second frequency domain 1070 (1055). UEmultiplexing is required for a layer of a resource area for MU-MIMO, andthus section fragmentation may be required. According to an embodiment,an RU may fragment a section for a specific layer. The RU may configurea control message to include information on the section fragmentation.For example, an extension field may include information (e.g., portnumber indication) on a layer to be fragmented. The extension field mayinclude location information (e.g., RB offset) of an RB required to befragmented.

FIG. 11 illustrates an operation flow of the DU, for multi-layerscheduling according to an embodiment of the disclosure. A DUillustrates the DU 160 of FIG. 2 .

Referring to FIG. 11 , in operation 1101, a DU may identify a designatedtransmission path. The DU may identify one or more transmission pathsamong a plurality of layers. The identified path may be a pathdesignated to represent the plurality of layers. According to anembodiment, designation of the transmission path may be performed in amanagement plane (M-plane of O-RAN). For the management plane (M-plane),“eAxC ID #A={eAxC ID #0, eAxC ID #1, eAxC ID #2, eAxC ID #(N−1)} (A isone of #0 to #N−1)” may be designated. A representative eAxCs for atotal of N layers may be designated.

In operation 1103, the DU may generate a control message based onmulti-layer scheduling. Multi-layer scheduling refers to a procedure ofallocating resources for a plurality of streams. A stream may correspondto a port (e.g., an antenna port) of an RU. A scheduler of a basestation may perform resource allocation for the plurality of streamswithin a designated time-frequency domain (e.g., section). The DU maygenerate the control message according to a result of the scheduling.

The DU may generate the control message including section information,beam information, and flow information. The DU may generate sectioninformation according to the scheduling result. For example, the sectioninformation may include information (e.g., frame, subframe, slot, andsymbol) on the time domain, information on the frequency domain (e.g.,RB and reMASK), and information (e.g., section ID) on the section. TheDU may configure the control message to include the section information.The DU may generate beam information according to the scheduling result.Resources that are spatially distinguished may also be included in thescheduling result. For example, the DU may generate beam information sothat the beam information includes at least one of a parameter (e.g.,beamID) related to a beam to be allocated to each terminal, a parameter(e.g., PMI) for precoding to be applied to layers of terminals, and aparameter related to MU-MIMO scheduling. The DU may generate flowinformation indicating the path identified in operation 1101. Forexample, for the corresponding information, a value may be configured sothat an “ecpriRtcid/ecpriPcid” field in an eCPRI header indicates aneAxC ID corresponding to the identified path, and the flow informationis generated so as to include the configured value.

In operation 1105, the DU may transmit the control message via afronthaul interface. For example, the DU may transmit the controlmessage based on at least one interface among an eCPRI and an O-RAN infronthaul interfaces. For example, the DU may use the header of theO-RAN to transfer the section information. The DU may use a sectionextension field of the O-RAN to transfer the beam information. The DUmay use the “ecpriRtcid/ecpriPcid” field in the eCPRI header in order totransfer the flow information.

FIG. 12 illustrates an operation flow of an RU, for multi-layerscheduling according to an embodiment of the disclosure. An RUillustrates the RU 180 of FIG. 3 .

Referring to FIG. 12 , in operation 1201, the RU may receive a controlmessage via a fronthaul interface. For example, the RU may transmit thecontrol message based on at least one interface among an eCPRI and anO-RAN in fronthaul interfaces. The RU may receive the control messagebased on at least one of header information of an eCPRI and headerinformation of an O-RAN. The control message may include multi-layerscheduling information.

In operation 1203, the RU may obtain multi-layer scheduling information.The multi-layer scheduling information may include section information,beam information, and flow information for a plurality of layers. Forexample, the RU may acquire multi-layer scheduling information based onat least one interface among the eCPRI and O-RAN in fronthaulinterfaces. For example, the RU may identify a header of the O-RAN toreceive the section information. The RU may obtain time-frequencyresources for wireless communication from the section information. TheRU may identify a section extension field of the O-RAN to receive thebeam information. The RU may obtain a weight vector to be applied toeach layer, from the beam information. The weight vector may be a beamweight vector based on a common beam or a weight vector corresponding toone column of a precoding matrix. The RU may identify an“ecpriRtcid/ecpriPcid” field in the eCPRI header to receive the flowinformation. The RU may identify a transmission path of thecorresponding control message from the flow information.

In operation 1205, the RU may perform multi-layer communication. The RUmay transmit scheduling information to a terminal and may performdownlink communication for performing multi-layer transmission. The RUmay transmit data streams to the terminal by applying a weight matrixaccording to the scheduling information. Alternatively, the RU maytransmit the scheduling information to the terminal, and may performuplink communication for receiving multi-layer transmission from theterminal. The RU may provide the terminal with information on the weightmatrix according to the scheduling information.

According to various embodiments, by configuring a simplified controlmessage for multiple layers and transmitting the control message via adesignated path, resources consumed in a fronthaul interface between aDU and an RU may be reduced. For example, a processing load is reduced.A load for packet generation and processing of a control plane may bereduced in proportion to the number of sections reduced compared to abandwidth (BW) of the existing control plane. For example, a memoryrequirement load is reduced. Memory requirements may be reduced inproportion to the number of sections reduced compared to the bandwidth(BW) of the existing control plane. As the bandwidth in the fronthaul isreduced, consumed resources may be saved, thereby enabling efficientfronthaul operation. In particular, in an environment (e.g., FR2) wherelayers are increased or a plurality of antennas are used, the amount oftraffic that a base station basically has to process during schedulingincreases, and therefore gains due to an integrated control messageoperation scheme of the disclosure may be further increased. Forexample, performance for each NR frequency range may be derived as shownin Table 4 below. Here, an indicator for performance is the number ofsections of the control plane, which are required for cell support.

TABLE 4 NR Frequency Range Existing value Proposed scheme FR1 (100 MHz,8Layer) 952 133 (reduced to 14.0%) FR2 (100 MHz, 4Layer) 224  77(reduced to 34.4%)

According to embodiments, an operation method of a digital unit (DU) ofa base station in a wireless communication system comprise identifying adesignated path among a plurality of paths of a fronthaul interface thatconnects the DU and a radio unit (RU); generating a control message fora plurality of layers; and transmitting the control message to the RUvia the designated path. The control message comprises schedulinginformation for the plurality of layers.

In some embodiments, the plurality of layers comprise a first layer anda second layer, and the control message comprises a number of theplurality of layers, information indicating a first weight vector forthe first layer, and information indicating a second weight vector forthe second layer.

In some embodiments, the scheduling information comprises: sectioninformation indicating common resource allocation for the plurality oflayers, beam information related to a weight matrix for the plurality oflayers, and flow information indicating the designated path. The sectioninformation is included in a header of an open-radio access network(O-RAN) of the control message, the beam information is included in asection extension field of the control message, and the flow informationis included in “ecpriRtcid/ecpriPcid” of an enhanced common public radiointerface (eCPRI) header of the control message.

In some embodiments, the control message comprises type informationindicating a scheduling scheme for the plurality of layers, and thescheduling scheme comprises one of: a first scheme of applying a commonbeam to each layer, a second scheme of applying a precoding matrix tothe plurality of layers, or a third scheme of applying individualprecoding to each of the plurality of layers.

In some embodiments, if the type information indicates the first scheme,the weight matrix indicates a beamforming weight vector for a singlelayer, and if the type information indicates the second scheme, theweight matrix indicates the weight matrix for the plurality of layers.

In some embodiments, when all control parameters are commonly applied tolayers, the control message comprises an extension field.

In some embodiments, the extension field includes a beamGroupType, aweight vector indicated by beamID, and a number of ports numPortc formulti-layer transmission.

In some embodiments, resources are allocated for a plurality of layersof a single user, and the control message indicates resource allocationand beam information for each terminal according to a scheduling result.

In some embodiments, single-user scheduling and multi-user schedulingare mixed, and the control message indicates resource allocation andbeam information for each terminal according to a scheduling result.

According to embodiments, an operation method of a radio unit (RU) of abase station in a wireless communication system, comprises: receiving acontrol message for a plurality of layers from a digital unit (DU) via adesignated path among a plurality of paths of a fronthaul interface thatconnects the RU and the DU; identifying scheduling information for theplurality of layers based on the control message; and performingcommunication based on the scheduling information.

In some embodiments, the plurality of layers comprise a first layer anda second layer, and the control message comprises a number of theplurality of layers, information indicating a first weight vector forthe first layer, and information indicating a second weight vector forthe second layer.

In some embodiments, the scheduling information comprises: sectioninformation indicating common resource allocation for the plurality oflayers, beam information related to a weight matrix for the plurality oflayers, and flow information indicating the designated path. The sectioninformation is included in a header of an open-radio access network(O-RAN) of the control message, the beam information is included in asection extension field of the control message, and the flow informationis included in “ecpriRtcid/ecpriPcid” of an enhanced common public radiointerface (eCPRI) header of the control message.

In some embodiments, the control message comprises type informationindicating a scheduling scheme for the plurality of layers, and thescheduling scheme comprises one of: a first scheme of applying a commonbeam to each layer, a second scheme of applying a precoding matrix tothe plurality of layers, or a third scheme of applying individualprecoding to each of the plurality of layers.

In some embodiments, if the type information indicates the first scheme,the weight matrix indicates a beamforming weight vector for a singlelayer, and if the type information indicates the second scheme, theweight matrix indicates the weight matrix for the plurality of layers.

According to embodiments, a device of a digital unit (DU) of a basestation in a wireless communication system, the device comprises: atleast one processor configured to identify a designated path among aplurality of paths of a fronthaul interface that connects the DU and aradio unit (RU), generate a control message for a plurality of layers,and control the fronthaul interface to transmit the control message tothe RU via the designated path, and the control message comprisesscheduling information for the plurality of layers.

In some embodiments, the plurality of layers comprise a first layer anda second layer, and the control message comprises a number of theplurality of layers, information indicating a first weight vector forthe first layer, and information indicating a second weight vector forthe second layer.

In some embodiments, the scheduling information comprises: sectioninformation indicating common resource allocation for the plurality oflayers, beam information related to a weight matrix for the plurality oflayers, and flow information indicating the designated path. The sectioninformation is included in a header of an open-radio access network(O-RAN) of the control message, the beam information is included in asection extension field of the control message, and the flow informationis included in “ecpriRtcid/ecpriPcid” of an enhanced common public radiointerface (eCPRI) header of the control message.

In some embodiments, the control message comprises type informationindicating a scheduling scheme for the plurality of layers, and thescheduling scheme comprises one of: a first scheme of applying a commonbeam to each layer, a second scheme of applying a precoding matrix tothe plurality of layers, or a third scheme of applying individualprecoding to each of the plurality of layers.

In some embodiments, if the type information indicates the first scheme,the weight matrix indicates a beamforming weight vector for a singlelayer, and if the type information indicates the second scheme, theweight matrix indicates the weight matrix for the plurality of layers.

According to embodiments, a device of a radio unit (RU) of a basestation in a wireless communication system, the device comprising: atleast one transceiver; and at least one processor, wherein the at leastone processor is configured to: control a fronthaul interface, whichconnects the RU and a digital unit (DU), to receive a control messagefor a plurality of layers from the DU via a designated path among aplurality of paths of the fronthaul interface, identify schedulinginformation for the plurality of layers based on the control message,and control the at least one transceiver to perform communication basedon the scheduling information.

In some embodiments, the plurality of layers comprise a first layer anda second layer, and the control message comprises a number of theplurality of layers, information indicating a first weight vector forthe first layer, and information indicating a second weight vector forthe second layer.

In some embodiments, the scheduling information comprises: sectioninformation indicating common resource allocation for the plurality oflayers, beam information related to a weight matrix for the plurality oflayers, and flow information indicating the designated path. The sectioninformation is included in a header of an open-radio access network(O-RAN) of the control message, the beam information is included in asection extension field of the control message, and the flow informationis included in “ecpriRtcid/ecpriPcid” of an enhanced common public radiointerface (eCPRI) header of the control message.

In some embodiments, the control message comprises type informationindicating a scheduling scheme for the plurality of layers, and thescheduling scheme comprises one of: a first scheme of applying a commonbeam to each layer, a second scheme of applying a precoding matrix tothe plurality of layers, or a third scheme of applying individualprecoding to each of the plurality of layers.

In some embodiments, if the type information indicates the first scheme,the weight matrix indicates a beamforming weight vector for a singlelayer, and if the type information indicates the second scheme, theweight matrix indicates the weight matrix for the plurality of layers.

Methods disclosed in the claims and/or methods according to variousembodiments described in the specification of the disclosure may beimplemented by hardware, software, or a combination of hardware andsoftware.

When the methods are implemented by software, a computer-readablestorage medium for storing one or more programs (software modules) maybe provided. The one or more programs stored in the computer-readablestorage medium may be configured for execution by one or more processorswithin the electronic device. The at least one program may includeinstructions that cause the electronic device to perform the methodsaccording to various embodiments of the disclosure as defined by theappended claims and/or disclosed herein.

The programs (software modules or software) may be stored in nonvolatilememories including a random access memory and a flash memory, a readonly memory (ROM), an electrically erasable programmable read onlymemory (EEPROM), a magnetic disc storage device, a compact disc-ROM(CD-ROM), digital versatile discs (DVDs), or other type optical storagedevices, or a magnetic cassette. Alternatively, any combination of someor all of them may form a memory in which the program is stored.Further, a plurality of such memories may be included in the electronicdevice.

In addition, the programs may be stored in an attachable storage devicewhich may access the electronic device through communication networkssuch as the Internet, Intranet, Local Area Network (LAN), Wide LAN(WLAN), and Storage Area Network (SAN) or a combination thereof. Such astorage device may access the electronic device via an external port.Further, a separate storage device on the communication network mayaccess a portable electronic device.

In the above-described detailed embodiments of the disclosure, anelement included in the disclosure is expressed in the singular or theplural according to presented detailed embodiments. However, thesingular form or plural form is selected appropriately to the presentedsituation for the convenience of description, and the disclosure is notlimited by elements expressed in the singular or the plural. Therefore,either an element expressed in the plural may also include a singleelement or an element expressed in the singular may also includemultiple elements.

While the disclosure has been shown and described with reference tovarious embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the disclosure as definedby the appended claims and their equivalents.

What is claimed is:
 1. A method performed by a distributed unit (DU),the method comprising: generating a control plane (C-plane) messageincluding section information with a section extension field formultiple ports; and transmitting, to a radio unit (RU), the C-planemessage via a representative port of the multiple ports, wherein thesection information includes a beam identifier (ID) for therepresentative port.
 2. The method of claim 1, wherein the sectionextension field includes: beam group type information, and informationon a number N of extended antenna-carrier (eAxC) ports indicated by thesection extension field.
 3. The method of claim 2, wherein the beam IDfor the representative port is used as a common beam ID for all of the NeAxC ports, in case that the beam group type information indicates afirst type.
 4. The method of claim 2, wherein N consecutive beam IDssubsequent to the beam ID are applied to the N eAxC ports, in case thatthe beam group type information indicates a second type.
 5. The methodof claim 2, wherein the section extension field further includes N beamIDs or N UE IDs, and wherein the N beam IDs or N UE IDs are applied tothe N eAxC ports, in case that the beam group type information indicatesa third type.
 6. A method performed by a radio unit (RU), the methodcomprising: receiving, from a distributed unit (DU), a control plane(C-plane) message including section information with a section extensionfield for multiple ports via a representative port of the multipleports; and identifying the section information and the section extensionfield included in the C-plane message, wherein the section informationincludes a beam identifier (ID) for the representative port.
 7. Themethod of claim 6, wherein the section extension field includes: beamgroup type information, and information on a number N of extendedantenna-carrier (eAxC) ports indicated by the section extension field.8. The method of claim 7, wherein the beam ID for the representativeport is used as a common beam ID for all of the N eAxC ports, in casethat the beam group type information indicates a first type.
 9. Themethod of claim 7, wherein N consecutive beam IDs subsequent to the beamID are applied to the N eAxC ports, in case that the beam group typeinformation indicates a second type.
 10. The method of claim 7, whereinthe section extension field further includes N beam IDs or N UE IDs, andwherein the N beam IDs or N UE IDs are applied to the N eAxC ports, incase that the beam group type information indicates a third type.
 11. Adevice of a distributed unit (DU), the device comprising: at least onetransceiver; and at least one processor configured to: generate acontrol plane (C-plane) message including section information with asection extension field for multiple ports, and transmit, to a radiounit (RU), the C-plane message via a representative port of the multipleports, wherein the section information includes a beam identifier (ID)for the representative port.
 12. The device of claim 11, wherein thesection extension field includes: beam group type information, andinformation on a number N of extended antenna-carrier (eAxC) portsindicated by the section extension field.
 13. The device of claim 12,wherein the beam ID for the representative port is used as a common beamID for all of the N eAxC ports, in case that the beam group typeinformation indicates a first type.
 14. The device of claim 12, whereinN consecutive beam IDs subsequent to the beam ID are applied to the NeAxC ports, in case that the beam group type information indicates asecond type.
 15. The device of claim 12, wherein the section extensionfield further includes N beam IDs or N UE IDs, and wherein the N beamIDs or N UE IDs are applied to the N eAxC ports, in case that the beamgroup type information indicates a third type.
 16. A device of a radiounit (RU), the device comprising: at least one transceiver; and at leastone processor configured to: receive, from a distributed unit (DU), acontrol plane (C-plane) message including section information with asection extension field for multiple ports via a representative port ofthe multiple ports, and identify the section information and the sectionextension field included in the C-plane message, wherein the sectioninformation includes a beam identifier (ID) for the representative port.17. The device of claim 16, wherein the section extension fieldincludes: beam group type information, and information on a number N ofextended antenna-carrier (eAxC) ports indicated by the section extensionfield.
 18. The device of claim 17, wherein the beam ID for therepresentative port is used as a common beam ID for all of the N eAxCports, in case that the beam group type information indicates a firsttype.
 19. The device of claim 17, wherein N consecutive beam IDssubsequent to the beam ID are applied to the N eAxC ports, in case thatthe beam group type information indicates a second type.
 20. The deviceof claim 17, wherein the section extension field further includes N beamIDs or N UE IDs, and wherein the N beam IDs or N UE IDs are applied tothe N eAxC ports, in case that the beam group type information indicatesa third type.